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I. M. Dremin

Publications and source records attributed to I. M. Dremin.

At least 55 records · Page 3Linked to original sources
arXiv2011

The quark-gluon medium (micro- and macro-QCD)

The properties of the quark-gluon medium observed in high energy nucleus-nucleus collisions are discussed. The main experimental facts about these collisions are briefly described and compared with data about proton-proton collisions. Both microscopic and macroscopic approaches to their description are reviewed. The chromodynamics of the quark-gluon medium at high energies is mainly considered. The energy loss of partons moving in this medium is treated. The principal conclusion is that the medium possesses some collective properties which are crucial for understanding the experimental observations.

hep-ph↗
arXiv2010

The quark-gluon medium

The properties of the quark-gluon medium observed in high energy nucleus-nucleus collisions are discussed. The main experimental facts about these collisions are briefly described and compared with data about proton-proton collisions. Both microscopic and macroscopic approaches to their description are reviewed. The chromodynamics of the quark-gluon medium at high energies is mainly considered. The energy loss of partons moving in this medium is treated. The principal conclusion is that the medium possesses some collective properties which are crucial for understanding the experimental observations.

nucl-th↗
arXiv2010

Polarization properties of the quark-gluon medium

Collective properties of the quark-gluon medium induced by its polarization are described by macroscopic QCD equations. The parton currents traversing it lead to emission of Cherenkov gluons, the wake effect and the transition radiation. Comparison with experimental data of RHIC reveals large value of the chromopermittivity of the medium while cosmic ray data at higher energies (close to LHC) favor much smaller values. The dispersion equations show that the proper modes of the medium are unstable.

hep-ph↗
arXiv2010

Some remarks about the transition gluon radiation

The electrodynamical formulae for the transition radiation are applied to the case of partons crossing the surface of the deconfined region in heavy ion collisions. The chromopermittivity is used in place of the dielectric permittivity. The corresponding energy-angular distributions of emitted gluons are discussed. They could be of interest at LHC energies.

hep-ph↗
arXiv2010

Equations, chromopermittivity and instabilities of the quark-gluon medium

The quark-gluon medium described by QCD equations is considered at high energies. Within the assumptions of the linear response theory the chromopermittivity of the medium is introduced and it is argued that it exceeds 1 at TeV energies. The dispersion equations show that the proper modes of the medium reveal instability and the parton currents traversing it induce the emission of Cherenkov gluons. Their distributions at LHC can differ from those typical for lower energies of RHIC because they are determined by the high energy dependence of the chromopermittivity while the latter ones arise due to collective resonance excitations. The distinction between Cherenkov gluons and Mach waves is discussed.

hep-ph↗
arXiv2009

The wake in mid-central nuclear collisions

It is argued that PHENIX collaboration observed for the first time the radiation of the longitudinal wake oscillations formed behind the parton penetrating the quark-gluon medium. It shifts the maximum of a hump in two-particle correlations and changes its width in the case of some special orientation of the trigger particle.

nucl-th↗
arXiv2009

Cherenkov Glue in Opaque Nuclear Medium

The spectrum of Cherenkov gluons is calculated within the framework of in-medium QCD. It is compared with experimental data on the double-humped structure around the away-side jet obtained at RHIC. The values of the real and imaginary parts of the nuclear permittivity are obtained from these fits. It is shown that accounting for an additional smearing due to resonance-like production of final hadrons allows to achieve an agreement with experimental data.

hep-ph↗
arXiv2009

QCD in the nuclear medium and effects due to Cherenkov gluons

The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes emission of Cherenkov gluons resembling results of classical electrodynamics. The values of the real and imaginary parts of the nuclear permittivity are obtained from the fits to experimental data on the double-humped structure around the away-side jet obtained at RHIC. The dispersion of the nuclear permittivity is predicted by comparing the RHIC, SPS and cosmic ray data. This is important for LHC experiments. Cherenkov gluons may be responsible for the asymmetry of dilepton mass spectra near rho-meson, observed in the SPS experiment with excess in the low-mass wing of the resonance. This feature is predicted to be common for all resonances. The "color rainbow" quantum effect might appear according to higher order terms of in-medium QCD if the nuclear permittivity depends on color.

hep-ph↗
arXiv2008

The nimbus of away-side jets

The conical structure around the away-side jets is discussed. The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes the shock wave induced by emission of Cherenkov gluons. The values of real and imaginary parts of nuclear permittivity are estimated from fits of RHIC data. Specific effects at LHC energies are described.

hep-ph↗
arXiv2008

In-medium QCD and Cherenkov gluons

The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes emission of Cherenkov gluons resembling results of classical electrodynamics. The choice of nuclear permittivity and Lorentz-invariance of the problem are discussed. Effects induced by the transversely and longitudinally moving (relative to the collision axis) partons at LHC energies are described.

hep-ph↗
arXiv2008

In-medium QCD and Cherenkov gluons vs Mach waves at LHC

The equations of in-medium gluodynamics are proposed. Their classical lowest order solution is explicitly shown for a color charge moving with constant speed. For nuclear permittivity larger than 1 it describes the shock wave induced by emission of Cherenkov gluons. Specific effects at LHC energies are described and compared with Mach wave predictions.

hep-ph↗
arXiv2007

Two-dimensional discrete wavelet analysis of multiparticle event topology in heavy ion collisions

The event-by-event analysis of multiparticle production in high energy hadron and nuclei collisions can be performed using the discrete wavelet transformation. The ring-like and jet-like structures in two-dimensional angular histograms are well extracted by wavelet analysis. For the first time the method is applied to the jet-like events with background simulated by event generators, which are developed to describe nucleus-nucleus collisions at LHC energies. The jet positions are located quite well by the discrete wavelet transformation of angular particle distribution even in presence of strong background.

nucl-ex↗
arXiv2007

The role of energy-momentum conservation in emission of Cherenkov gluons

The famous formula for the emission angle of Cherenkov radiation should be modified when applied to hadronic reactions because of recoil effects. They impose the upper limit on the energy of the gluon emitted at a given angle. Also, it leads to essential corrections to the nuclear refractive index value as determined from the angular position of Cherenkov rings.

hep-ph↗
arXiv2007

Cherenkov gluons (predictions and proposals)

The coherent hadron production analogous to Cherenkov radiation of photons gives rise to the ring-like events. Being projected on the ring diameter they produce the two-bump structure recently observed for the away-side jets at RHIC. The position of the peaks and their height determine such properties of the hadronic medium as its nuclear refractive index, the parton density, the free path length and the energy loss of Cherenkov gluons. Cherenkov gluons may be responsible for the asymmetry of dilepton mass spectra near rho-meson observed in experiment. Beside comparatively low energy gluons observed at RHIC, there could be high energy gluons at LHC, related to the high energy region of positive real part of the forward scattering amplitude and possessing different characteristics. This would allow to scan (x, Q^2)-plane determining the parton densities in its various regions.

hep-ph↗
arXiv2007

Asymmetry of in-medium rho-mesons as a signature of Cherenkov effects

Cherenkov gluons may be responsible for the asymmetry of dilepton mass spectra near rho-meson observed in experiment. They can be produced only in the low-mass wing of the resonance. Therefore the dilepton mass spectra are flattened there and their peak is slightly shifted to lower masses compared with the in-vacuum rho-meson mass. This feature must be common for all resonances.

hep-ph↗
arXiv2007

The two types of Cherenkov gluons at LHC energies

Beside comparatively low energy Cherenkov gluons observed at RHIC, there could be high energy gluons at LHC, related to the high energy region of positive real part of the forward scattering amplitude. In both cases they give rise to particles emitted along some cone. The characteristics of the cones produced by these two types of gluons are different. Therefore different experiments are needed to detect them. The cosmic ray event which initiated this idea is described in detail.

hep-ph↗